NO. This kind of system can and WILL be abused to hell, trust me. The GSHC tried to do something like it, and now it's devolved into "If you don't like someone, Rep-bomb them". After I got an admin fired for abuse of power there, I went from +80 rep, to -270 or so. The webmaster had to step in and try and fix it, but I'm still down to about -30 after that. There's still some people bitter at me over there, so if I ever do anything that, according to them, "crosses the line" such as reporting them when they break the rules (like any good girl should), I tend to get -5 or so at a time.

Instead, IF you decide to do something, make it a "Like system" or "thank system".

One use for an upvote system is for approving of posts without actually posting in there. For discussions (and even arguments), it can help legitimize the opinions of some peeps. Maybe it's good for people who like to lurk?

It brings spiteful action. People will start downvoting in retaliation to things they don't like. For example, let's say I got an admin fired. Well, said admin was bitter, made an alt account, and used it to spam the downvote so that I was several hundred rep negative.

No, I'm not talking recent events. I'm saying exactly what happened at the GSHC last April. The system in use at the GSHC is abused to hell and back, and admin intervention to stop that abuse has only had limited success. If you say something that someone doesn't like, they won't downvote that one post - they'll downvote every post in the thread you made. It happened recently when I dared to ask people if they wanted to evolve the purpose of the GSHC in order to actually get some activity in the place. Apparently, I was wrong to want the place lively.